US patent 6,542,270 ("Interference-robust coded-modulation scheme for optical communications and method for modulating illumination for optical communications"), issued April 1, 2003, assigns direct sequence spread spectrum-type codes to each overhead fluorescent light, so that communication and location-determination can be performed. The chip frequency of the coding scheme is fast enough that there is no human-audible or -visual effect, and supportable by electronic ballasts.
... is the 20th Anniversary of the 802.11 Working Group itself. The Working Group held its first meeting September 10-14, 1990, in Oshawa, Ontario, Canada.
... the article linked in the story starts off by debunking the submission.
UPDATE (March 10, 12:45am PST): With thanks to Prof. Jon Butterworth, member of the ATLAS collaboration at the LHC, I've been informed that the plan to shut down the LHC for an extended period of time was actually announced in early February by Dr. Steve Myers after the LHC Performance Workshop, in Chamonix, France. So rather than this being a sudden development, it is part of a planned shutdown.
Typographical errors occur more often than one would think in patent applications. Often they're because the typist is unfamiliar with technical terms or can't read the inventor's handwriting. Or, maybe, the typist is daydreaming about a lobster dinner:
The independent claims in the application (20100045241, filed August 20, 2008) center on the use of the battery's mass to generate electricity via one or more piezoelectric elements. It's always nice to see a liability turned into an asset. While this is just an application, and the claims may differ substantially in the issued patent (should one issue at all), here is the first independent claim:
1. An apparatus comprising:
a device housing;
a holder configured to retain a battery;
a first piezoelectric element coupling the holder to the device housing and configured to receive, as a result of acceleration of the device housing and along a first axis, a first portion of a force of imposed by a mass of a battery retained in the holder;
a second piezoelectric element coupling the holder to the device housing and configured to receive, as a result of the device housing acceleration and along a second axis that is non-parallel to the first axis, a second portion of the force imposed by the mass of the battery retained in the holder; and
a controller configured to receive electrical energy output by the first and second piezoelectric elements in response to the first and second force portions and to make the received electrical energy available for at least one of:
satisfying at least part of an electrical load satisfiable by the battery retained in the holder, and
recharging the battery retained in the holder.
So it's key to (a) use the battery as the mass, and (b) generate electrical energy from two nonparallel piezoelectric elements. Note that nowhere does the claim mention a phone, just "a device," so this could have relatively wide applicability -- should it issue as written.
Lots of demo software is designed to stop working entirely after the demo period expires. The concept of doing this gradually over time seems, if anything, more humane.
I suggest we roll over and go back to sleep -- or at least save our angst for worthy matters.
The bimonthly IEEE 802.11 standards meetings are co-located with other 802 wireless working groups (802.15, 16, et al.) and regularly have attendance from 600-1000 persons, substantially all of whom are active on 2.4GHz (802.11b/g) substantially all the time the meetings are in session (it's required to register session attendance, upload and download documents, etc., but is largely used for Internet-based multitasking). These networks have worked flawlessly for years. They are specially-built for the meetings by VeriLAN Event Services, a company specializing in network services for special events. Their web site claims that they have supported events with up to 5000 simultaneous users.
Granted, but it's also true that the indictment did not specify the operating overhead of the enterprise (except for some of its payroll), nor its cost of capital. These guys must have had seed money to set up the organization -- how much interest did they pay? It's likely in this case that this information is available to prosecutors, but just not in the indictment.
I think it's likely they used gross profit because (a) it makes the enterprise seem larger, and its indictment a bigger coup for the prosecutors, and (b) it's an easier number to get -- no messy going through rent and electric bill receipts. Criminal enterprises rarely have audited books.
The indictment actually states that, ". ..Wiseguys and its owners made more than $20 million in profits. .." (p. 2 of the indictment), so let's start with the $20 million number.
Keep in mind that:
(a) The $20 million was made over an eight-year period, 2002-2009, so the average was $2.5 million/year;
(b) The profit of the enterprise was split among the two principals (the CFO received $165,000 and the programmer received $150,000, natch...), so that brings it down to an average of $1.25 million/year for the two principals (I think we can agree that the salaried guys did not do well in their risk/reward ratio calculations); and
(c) The "profit" figure used in indictments is nearly always what a legitimate businessperson would call "gross profit," meaning, to quote Wikipedia, "the difference between revenue and the cost of making a product or providing a service, before deducting overhead, payroll, taxation, and interest payments." As a criminal enterprise, these guys didn't have to worry about taxation (at least, the correct amount of taxation), but they did have to pay the salaries of the other 10-15 people working for Wiseguys Tickets, Inc., and all the other expenses associated with running the enterprise (computers... ). All of that would have to come out that $1.25 million/year/indictable person. A quick look through the indictment shows the several persons on staff in the US being paid from $55k to $142k/year each, and the ones in Bulgaria being paid from $1 to $1.5k/month each, so you do the math.
The point being, the retirement plan associated with these types of schemes is typically poor, as it's usually at a federally-funded establishment. These guys ran a small tech company with overseas offices, and could have done the same legitimately at a salary of probably $150k/year which, once benefits were included, would be equivalent to $250k/year in cash (to make a direct comparison to their criminal enterprise). In a legitimate business, the CEO also would have had significant stock options and other perks given to him by the company's board to motivate him to grow the company. With even moderate growth over that period, the CEO could be very well-off. As I say, it's easier to make money legitimately.
You're mixing up two effects. You're correct that the direct EM radiation would affect largely only the sunlit portion of the Earth. However, the "second punch" of these events is the large burst of protons that arrives the next day -- it's the solar wind, but several orders of magnitude larger than usual.
These protons are affected by the geomagnetic field, and (to simplify a lot) rain down in large regions generally centered around the magnetic poles (cf. the auroral ovals), where they induce very large currents in long conductors like power lines, leading to general power failures that could not be easily repaired.
This wouldn't be your garden-variety blackout -- it would require physical replacement of massive equipment for which there are no spares readily available -- at least not in the quantities needed. Large numbers of people -- entire provinces and states in North America, and likely entire nations in northern Europe -- would be without power for months while new equipment was manufactured and installed. This would lead to mass migrations out of these areas, which would lead to social disruption and significant loss of life as critical systems, whose backup generators and other emergency systems were not designed for such an extended outage, failed.
I was in south Florida for Hurricane Wilma, and I can report to you that the social structure of the region almost broke down during the week or two the region was without electricity -- and this was a natural disaster, albeit a severe one, that people understood and had largely prepared for. Power was restored relatively quickly then, because (a) the causes, downed power lines, were easy to find and repair, and (b) there was a massive influx of utility workers from the rest of the country to help out. In a solar flare scenario, the cause would be much harder to fix, and there would be a much larger affected area (and, consequently, a much smaller unaffected area from which to draw support).
We discussed the chemists' war on Prohibition in high school history, and I always assumed it was common knowledge. Admittedly, that was back when dirt was new, but geez -- is this really news to people?
...but that is exactly my point. Feynman himself noted the "victory disease" that developed at NASA when successful launch followed successful launch -- those warning of imminent disaster were dismissed because, well, they just couldn't be right, and they had a history of successful launches to prove it. All the detractors had as evidence was charred O-rings, and some wacky theory about cold-temperature elasticity.
In these cases the successful launches were less than valuable -- they actually taught the wrong thing. They taught that the system was safe when, in fact, it wasn't, and the fact that they were really close calls wasn't apparent until the system actually failed. The failure showed just how close to the edge they actually were.
In any engineering system at all, there is a substantially infinite number of ways in which it could fail. Just list the number of ways a torch (flashlight) can fail, beginning from first principles:
--mechanical opening of the electrical circuit; --battery failure (as opposed to simple exhaustion, which can be considered at the design phase); --switch failure; --bulb failure; --etc.
It's very, very difficult to look at this list and predict a priori (meaning without any field failure experience) the failure rate of each of these failure mechanisms, so that the overall failure rate of the system can be predicted. Any engineer will tell you that there are always failure mechanisms that are not fully understood (people and programs don't live forever); any manager will tell you that engineers are always concerned about what might go wrong (it's what separates them from marketing droids, who are always concerned about what's expected to go right). For this reason, there's a natural inclination for managers to stop asking engineers about possible disaster scenarios -- and to stop listening to the engineers when they bring them up. A lot of it is just fatigue.
Wald's famous bomber studies actually prove my point: He actually had failures; he just didn't have access to the crash sites. The correct comparison would be a hypothetical one, to some poor sot asked to figure out where to armor the bombers, when none of the bombers had ever been shot down. Without any failures (i.e., if the bombers always came back), the "correct" deduction would be to continually reduce the amount of armor on the bombers, since the weight of the armor could be traded for more bombs, fuel, or traded for higher aircraft performance (speed, rate of climb, or service altitude, since the plane would be lighter). The armor engineer could protest, citing his studies of how easily such a plane could be shot down, and perhaps even showing bullet holes and other evidence of near-disaster, but his cries would fall on deaf ears, until the planes started being shot down -- i.e., until the first failures occurred.
Keep in mind that SpaceX can learn from launch successes too.
True, but any engineer will tell you that you learn far more from your failures than your successes. Failures teach you what technical parameters -- including those that you may have overlooked or considered unimportant, like O-ring behavior at low temperatures and the effects of foam striking tile -- are required for successful operation. They also give you a clue about margins of safety: Without a failure, one can theorize but never truly know how close a design is to disaster. With failures, it's possible to know how far the envelope can be pushed -- which engineering trades (weight for strength, battery size for operating lifetime, etc.) can be made, and which cannot.
I've always considered the quandary discussed in this thread -- whether failures should be desired at the beginning of a development program, or later on -- to be the fundamental problem of all product development programs. It's common in all commercial engineering with which I'm familiar: In a large company, a product team whose first prototype is a flop is frequently not allowed the opportunity for a second try, since there are always more potential products to be developed than engineers to develop them, and it's too easy to reassign the engineers to another, "more successful," project. And yet, there is nothing more expensive than engineering changes late in the development cycle, especially if they are the result of catastrophic public failure.
I've come to the conclusion that the important ingredient, surprisingly enough, is faith: The engineers and their management have to have a belief, not supported by independently-verifiable facts a priori, that such-and-such technology is achievable and will be successful. This faith will enable the project to survive its early failures, where much is learned by the engineering staff but without external evidence of progress, to produce a final product that is both reliable and successful.
In hindsight, it's common to look at such programs and see them as a "natural" progression of technology, much like the development of integrated circuits in the 1960s, without realizing that, at the time of the start of their development, the arguments against them were at least as compelling as the arguments for them. This viewpoint is often encouraged by situations like the Cold War, in which vast sums of public money are spent on an incredible variety of technology development programs; the successful ones (like missiles and integrated circuits) are remembered, and the unsuccessful ones are not. (I'd give examples of some of the unsuccessful ones, but none come to mind. . ..)
While we're on the subject of timepieces powered by their environment, may I present the Atmos Clock, which is powered solely by the small changes in temperature and atmospheric pressure that occur naturally every day. It was designed by Jean-Léon Reutter in 1928, and over half a million have been sold to date.
It's hard to tell from the photograph, but I think the circular circuit board is a probe ring for an automated integrated circuit tester. The chip is placed in the hole in the center of the circuit board. Probe pins, like these, are placed on the gold area around the hole in the center to contact the pads of the IC under test. The other side of the pins are connected to the inner ring of contact points on the circuit board (just outside the gold area), which are, in turn, connected to the rows of contact points at the periphery of the board. These points are big enough for human beings to connect test equipment cables to.
It's an example of the transition needed from the micro- (or even nano-) world of integrated circuits to the human-scale physical world.
I guess SourceForge has vetted this process with its attorneys, but I must be missing something. If a project admin opens up his project's block, he's personally criminally liable should some citizen of a country on the wrong list see a controlled technology from one of SourceForge's servers. That's scary enough for US citizens residing in the US. However, SourceForge doesn't provide the admins (AFAIK) with any export control training, or even vet their citizenship; an admin in Syria, with Syrian citizenship, who did this would seem to be out of reach of the US, which would then fall back to SourceForge, since it did not control access to the technology on its servers. Unless SourceForge has now asked to see citizenship papers of each of its project admins... ?
License Requirement Note: When a person performs or provides technical assistance that incorporates, or otherwise draws upon, “technology” that was either obtained in the United States or is of US-origin, then a release of the “technology” takes place. Such technical assistance, when rendered with the intent to aid in the “development” or “production” of encryption commodities or software that would be controlled for “EI” reasons under ECCN 5A002 or 5D002.a or 5D002.c, may require authorization under the EAR even if the underlying encryption algorithm to be implemented is from the public domain or is not of U.S. origin.
I think you'll find that CW has a signal bandwidth equal to or less than that of PSK31, when sent at the same data rate. If you doubt the textbooks, this is easy to see for yourself, by having someone send CW while you look at the signal on the waterfall display of your favorite PSK receiving software -- or just tune down to the CW portion of the band and have a look.
People often use filter bandwidths of 500 Hz (or even more) while manually receiving CW, just for ease of tuning, and let their brains do the "channel filtering" to separate individual CW signals present in that bandwidth. Similarly, people often use filter bandwidths of 2.4 kHz when receiving PSK31, just for ease of tuning, then let their computer do the "channel filtering" to separate the individual PSK signals present in that bandwidth.
You're comparing the signal bandwidth of PSK31, with the noise bandwidth of a CW receiver. The two are separate concepts.
There's also IEEE 802.15.6, "a [developing] communication standard optimized for low power devices and operation on, in or around the human body (but not limited to humans) to serve a variety of applications including medical, consumer electronics / personal entertainment..."
Companies interested in making on-body patches and plasters for medical applications are quite active in this group.
The IEEE-802.15.4 specification defines a way to reduce power, but it does not enshrine this at the MAC layer of this protocol. Perhaps Zigbee may do this, but it isn't in '15.4 as far as I have read.
That's correct; as I said, "I don't know of any protocol that does this." 15.4 does do CCA, and yes, it has the limitations you describe. The hidden terminal problem lives.
We arranged the 15.4 channels so that there would be one between each of the three non-overlapping 802.11 channels, plus a couple above Channel 11, figuring that if any portions of the spectrum were clear, those would be the spots.
The receiver power consumption in the first 15.4 receiver I designed (still being sold by a major IC house, despite being long in the tooth) was actually higher than that of the transmitter, due to a rather conservatively designed ADC. This was fixed, in a manner that can only be appreciated by a semiconductor marketing manager, by increasing the rated transmit power until the "right" relationship was attained.
Slashdot Mirror
Those interested in this LED-based technology can check out the IEEE 802.15.7 Visible Light Communication Task Group. Members of the Fraunhofer Institute are regular contributors to the standard.
US patent 6,542,270 ("Interference-robust coded-modulation scheme for optical communications and method for modulating illumination for optical communications"), issued April 1, 2003, assigns direct sequence spread spectrum-type codes to each overhead fluorescent light, so that communication and location-determination can be performed. The chip frequency of the coding scheme is fast enough that there is no human-audible or -visual effect, and supportable by electronic ballasts.
...is really just navel fluff; no military personnel were harmed in the making of this submission. [Insert witty rejoinder here]
The official name of 802 is the IEEE 802 "LAN/MAN Standards Committee," not the other way around.
... is the 20th Anniversary of the 802.11 Working Group itself. The Working Group held its first meeting September 10-14, 1990, in Oshawa, Ontario, Canada.
... the article linked in the story starts off by debunking the submission.
Typographical errors occur more often than one would think in patent applications. Often they're because the typist is unfamiliar with technical terms or can't read the inventor's handwriting. Or, maybe, the typist is daydreaming about a lobster dinner:
The same day the kinetic energy patent application was published, the USPTO published this one: SOFT BUTTER MEMORY CONFIGURATION IN A COMMUNICATION SYSTEM.
It, of course, refers to a "soft buffer" memory configuration, but which patent is likely to have less prior art?
The independent claims in the application (20100045241, filed August 20, 2008) center on the use of the battery's mass to generate electricity via one or more piezoelectric elements. It's always nice to see a liability turned into an asset. While this is just an application, and the claims may differ substantially in the issued patent (should one issue at all), here is the first independent claim:
1. An apparatus comprising:
a device housing;
a holder configured to retain a battery;
a first piezoelectric element coupling the holder to the device housing and configured to receive, as a result of acceleration of the device housing and along a first axis, a first portion of a force of imposed by a mass of a battery retained in the holder;
a second piezoelectric element coupling the holder to the device housing and configured to receive, as a result of the device housing acceleration and along a second axis that is non-parallel to the first axis, a second portion of the force imposed by the mass of the battery retained in the holder; and
a controller configured to receive electrical energy output by the first and second piezoelectric elements in response to the first and second force portions and to make the received electrical energy available for at least one of:
satisfying at least part of an electrical load satisfiable by the battery retained in the holder, and
recharging the battery retained in the holder.
So it's key to (a) use the battery as the mass, and (b) generate electrical energy from two nonparallel piezoelectric elements. Note that nowhere does the claim mention a phone, just "a device," so this could have relatively wide applicability -- should it issue as written.
Lots of demo software is designed to stop working entirely after the demo period expires. The concept of doing this gradually over time seems, if anything, more humane.
I suggest we roll over and go back to sleep -- or at least save our angst for worthy matters.
The bimonthly IEEE 802.11 standards meetings are co-located with other 802 wireless working groups (802.15, 16, et al.) and regularly have attendance from 600-1000 persons, substantially all of whom are active on 2.4GHz (802.11b/g) substantially all the time the meetings are in session (it's required to register session attendance, upload and download documents, etc., but is largely used for Internet-based multitasking). These networks have worked flawlessly for years. They are specially-built for the meetings by VeriLAN Event Services, a company specializing in network services for special events. Their web site claims that they have supported events with up to 5000 simultaneous users.
Granted, but it's also true that the indictment did not specify the operating overhead of the enterprise (except for some of its payroll), nor its cost of capital. These guys must have had seed money to set up the organization -- how much interest did they pay? It's likely in this case that this information is available to prosecutors, but just not in the indictment.
I think it's likely they used gross profit because (a) it makes the enterprise seem larger, and its indictment a bigger coup for the prosecutors, and (b) it's an easier number to get -- no messy going through rent and electric bill receipts. Criminal enterprises rarely have audited books.
The indictment actually states that, ". . .Wiseguys and its owners made more than $20 million in profits. . ." (p. 2 of the indictment), so let's start with the $20 million number.
Keep in mind that:
(a) The $20 million was made over an eight-year period, 2002-2009, so the average was $2.5 million/year;
(b) The profit of the enterprise was split among the two principals (the CFO received $165,000 and the programmer received $150,000, natch...), so that brings it down to an average of $1.25 million/year for the two principals (I think we can agree that the salaried guys did not do well in their risk/reward ratio calculations); and
(c) The "profit" figure used in indictments is nearly always what a legitimate businessperson would call "gross profit," meaning, to quote Wikipedia, "the difference between revenue and the cost of making a product or providing a service, before deducting overhead, payroll, taxation, and interest payments." As a criminal enterprise, these guys didn't have to worry about taxation (at least, the correct amount of taxation), but they did have to pay the salaries of the other 10-15 people working for Wiseguys Tickets, Inc., and all the other expenses associated with running the enterprise (computers ... ). All of that would have to come out that $1.25 million/year/indictable person. A quick look through the indictment shows the several persons on staff in the US being paid from $55k to $142k/year each, and the ones in Bulgaria being paid from $1 to $1.5k/month each, so you do the math.
The point being, the retirement plan associated with these types of schemes is typically poor, as it's usually at a federally-funded establishment. These guys ran a small tech company with overseas offices, and could have done the same legitimately at a salary of probably $150k/year which, once benefits were included, would be equivalent to $250k/year in cash (to make a direct comparison to their criminal enterprise). In a legitimate business, the CEO also would have had significant stock options and other perks given to him by the company's board to motivate him to grow the company. With even moderate growth over that period, the CEO could be very well-off. As I say, it's easier to make money legitimately.
And you sleep better.
Wouldn't it have been easier just to make the money legitimately?
You're mixing up two effects. You're correct that the direct EM radiation would affect largely only the sunlit portion of the Earth. However, the "second punch" of these events is the large burst of protons that arrives the next day -- it's the solar wind, but several orders of magnitude larger than usual.
These protons are affected by the geomagnetic field, and (to simplify a lot) rain down in large regions generally centered around the magnetic poles (cf. the auroral ovals), where they induce very large currents in long conductors like power lines, leading to general power failures that could not be easily repaired.
This wouldn't be your garden-variety blackout -- it would require physical replacement of massive equipment for which there are no spares readily available -- at least not in the quantities needed. Large numbers of people -- entire provinces and states in North America, and likely entire nations in northern Europe -- would be without power for months while new equipment was manufactured and installed. This would lead to mass migrations out of these areas, which would lead to social disruption and significant loss of life as critical systems, whose backup generators and other emergency systems were not designed for such an extended outage, failed.
I was in south Florida for Hurricane Wilma, and I can report to you that the social structure of the region almost broke down during the week or two the region was without electricity -- and this was a natural disaster, albeit a severe one, that people understood and had largely prepared for. Power was restored relatively quickly then, because (a) the causes, downed power lines, were easy to find and repair, and (b) there was a massive influx of utility workers from the rest of the country to help out. In a solar flare scenario, the cause would be much harder to fix, and there would be a much larger affected area (and, consequently, a much smaller unaffected area from which to draw support).
We discussed the chemists' war on Prohibition in high school history, and I always assumed it was common knowledge. Admittedly, that was back when dirt was new, but geez -- is this really news to people?
I always thought it was Unafordium.
...but that is exactly my point. Feynman himself noted the "victory disease" that developed at NASA when successful launch followed successful launch -- those warning of imminent disaster were dismissed because, well, they just couldn't be right, and they had a history of successful launches to prove it. All the detractors had as evidence was charred O-rings, and some wacky theory about cold-temperature elasticity.
In these cases the successful launches were less than valuable -- they actually taught the wrong thing. They taught that the system was safe when, in fact, it wasn't, and the fact that they were really close calls wasn't apparent until the system actually failed. The failure showed just how close to the edge they actually were.
In any engineering system at all, there is a substantially infinite number of ways in which it could fail. Just list the number of ways a torch (flashlight) can fail, beginning from first principles:
--mechanical opening of the electrical circuit;
--battery failure (as opposed to simple exhaustion, which can be considered at the design phase);
--switch failure;
--bulb failure;
--etc.
It's very, very difficult to look at this list and predict a priori (meaning without any field failure experience) the failure rate of each of these failure mechanisms, so that the overall failure rate of the system can be predicted. Any engineer will tell you that there are always failure mechanisms that are not fully understood (people and programs don't live forever); any manager will tell you that engineers are always concerned about what might go wrong (it's what separates them from marketing droids, who are always concerned about what's expected to go right). For this reason, there's a natural inclination for managers to stop asking engineers about possible disaster scenarios -- and to stop listening to the engineers when they bring them up. A lot of it is just fatigue.
Wald's famous bomber studies actually prove my point: He actually had failures; he just didn't have access to the crash sites. The correct comparison would be a hypothetical one, to some poor sot asked to figure out where to armor the bombers, when none of the bombers had ever been shot down. Without any failures (i.e., if the bombers always came back), the "correct" deduction would be to continually reduce the amount of armor on the bombers, since the weight of the armor could be traded for more bombs, fuel, or traded for higher aircraft performance (speed, rate of climb, or service altitude, since the plane would be lighter). The armor engineer could protest, citing his studies of how easily such a plane could be shot down, and perhaps even showing bullet holes and other evidence of near-disaster, but his cries would fall on deaf ears, until the planes started being shot down -- i.e., until the first failures occurred.
True, but any engineer will tell you that you learn far more from your failures than your successes. Failures teach you what technical parameters -- including those that you may have overlooked or considered unimportant, like O-ring behavior at low temperatures and the effects of foam striking tile -- are required for successful operation. They also give you a clue about margins of safety: Without a failure, one can theorize but never truly know how close a design is to disaster. With failures, it's possible to know how far the envelope can be pushed -- which engineering trades (weight for strength, battery size for operating lifetime, etc.) can be made, and which cannot.
I've always considered the quandary discussed in this thread -- whether failures should be desired at the beginning of a development program, or later on -- to be the fundamental problem of all product development programs. It's common in all commercial engineering with which I'm familiar: In a large company, a product team whose first prototype is a flop is frequently not allowed the opportunity for a second try, since there are always more potential products to be developed than engineers to develop them, and it's too easy to reassign the engineers to another, "more successful," project. And yet, there is nothing more expensive than engineering changes late in the development cycle, especially if they are the result of catastrophic public failure.
I've come to the conclusion that the important ingredient, surprisingly enough, is faith: The engineers and their management have to have a belief, not supported by independently-verifiable facts a priori, that such-and-such technology is achievable and will be successful. This faith will enable the project to survive its early failures, where much is learned by the engineering staff but without external evidence of progress, to produce a final product that is both reliable and successful.
In hindsight, it's common to look at such programs and see them as a "natural" progression of technology, much like the development of integrated circuits in the 1960s, without realizing that, at the time of the start of their development, the arguments against them were at least as compelling as the arguments for them. This viewpoint is often encouraged by situations like the Cold War, in which vast sums of public money are spent on an incredible variety of technology development programs; the successful ones (like missiles and integrated circuits) are remembered, and the unsuccessful ones are not. (I'd give examples of some of the unsuccessful ones, but none come to mind. . . .)
While we're on the subject of timepieces powered by their environment, may I present the Atmos Clock, which is powered solely by the small changes in temperature and atmospheric pressure that occur naturally every day. It was designed by Jean-Léon Reutter in 1928, and over half a million have been sold to date.
It's hard to tell from the photograph, but I think the circular circuit board is a probe ring for an automated integrated circuit tester. The chip is placed in the hole in the center of the circuit board. Probe pins, like these, are placed on the gold area around the hole in the center to contact the pads of the IC under test. The other side of the pins are connected to the inner ring of contact points on the circuit board (just outside the gold area), which are, in turn, connected to the rows of contact points at the periphery of the board. These points are big enough for human beings to connect test equipment cables to.
It's an example of the transition needed from the micro- (or even nano-) world of integrated circuits to the human-scale physical world.
I guess SourceForge has vetted this process with its attorneys, but I must be missing something. If a project admin opens up his project's block, he's personally criminally liable should some citizen of a country on the wrong list see a controlled technology from one of SourceForge's servers. That's scary enough for US citizens residing in the US. However, SourceForge doesn't provide the admins (AFAIK) with any export control training, or even vet their citizenship; an admin in Syria, with Syrian citizenship, who did this would seem to be out of reach of the US, which would then fall back to SourceForge, since it did not control access to the technology on its servers. Unless SourceForge has now asked to see citizenship papers of each of its project admins ... ?
This problem covers all sorts of technology far beyond encryption but, just to continue the encryption example, there is a little note on p. 7 of Category 5 (Part 2: Information Security) of the Commerce Control List:
This patent did not issue on Thursday. US patents always issue on Tuesdays. This one issued on 2 February.
The USPTO publishes patent applications (18 months after filing) on Thursdays.
I think you'll find that CW has a signal bandwidth equal to or less than that of PSK31, when sent at the same data rate. If you doubt the textbooks, this is easy to see for yourself, by having someone send CW while you look at the signal on the waterfall display of your favorite PSK receiving software -- or just tune down to the CW portion of the band and have a look.
People often use filter bandwidths of 500 Hz (or even more) while manually receiving CW, just for ease of tuning, and let their brains do the "channel filtering" to separate individual CW signals present in that bandwidth. Similarly, people often use filter bandwidths of 2.4 kHz when receiving PSK31, just for ease of tuning, then let their computer do the "channel filtering" to separate the individual PSK signals present in that bandwidth.
You're comparing the signal bandwidth of PSK31, with the noise bandwidth of a CW receiver. The two are separate concepts.
There's also IEEE 802.15.6, "a [developing] communication standard optimized for low power devices and operation on, in or around the human body (but not limited to humans) to serve a variety of applications including medical, consumer electronics / personal entertainment ..."
Companies interested in making on-body patches and plasters for medical applications are quite active in this group.
That's correct; as I said, "I don't know of any protocol that does this." 15.4 does do CCA, and yes, it has the limitations you describe. The hidden terminal problem lives.
We arranged the 15.4 channels so that there would be one between each of the three non-overlapping 802.11 channels, plus a couple above Channel 11, figuring that if any portions of the spectrum were clear, those would be the spots.
The receiver power consumption in the first 15.4 receiver I designed (still being sold by a major IC house, despite being long in the tooth) was actually higher than that of the transmitter, due to a rather conservatively designed ADC. This was fixed, in a manner that can only be appreciated by a semiconductor marketing manager, by increasing the rated transmit power until the "right" relationship was attained.